A magazine well for a firearm having an angled spine receiving portion. A charging handle for a firearm having latch that extends below a bottom surface of a crossbar. A bolt carrier for a firearm having a pair of vent holes disposed in the indented portion and at least one additional vent hole on indented portion adjacent to the pair of vent holes. A bolt catch for a firearm having a receiving portion curved to match the contours of a human thumb. A scope assembly for a firearm having markers on a scope and amount that correspond to the same radial positions. A bolt for a firearm having a plurality of ribs disposed on a main body and extending from a front end toward a tail portion of the bolt.

The present invention relates to an action bar (4) bushing apparatus that allows the action bar (4) to be fixed to the barrel (17), that changes as a retainer pin apparatus and/or lever apparatus depending on the use preference, and that has been developed to facilitate the removal of the action bar (4) in order to clean the rifle bolt (2) and parts thereof.

A magazine well for a firearm having an angled spine receiving portion. A charging handle for a firearm having latch that extends below a bottom surface of a crossbar. A bolt carrier for a firearm having a pair of vent holes disposed in the indented portion and at least one additional vent hole on indented portion adjacent to the pair of vent holes. A bolt catch for a firearm having a receiving portion curved to match the contours of a human thumb. A scope assembly for a firearm having markers on a scope and amount that correspond to the same radial positions. A bolt for a firearm having a plurality of ribs disposed on a main body and extending from a front end toward a tail portion of the bolt.

A magazine well for a firearm having an angled spine receiving portion. A charging handle for a firearm having latch that extends below a bottom surface of a crossbar. A bolt carrier for a firearm having a pair of vent holes disposed in the indented portion and at least one additional vent hole on indented portion adjacent to the pair of vent holes. A bolt catch for a firearm having a receiving portion curved to match the contours of a human thumb. A scope assembly for a firearm having markers on a scope and amount that correspond to the same radial positions. A bolt for a firearm having a plurality of ribs disposed on a main body and extending from a front end toward a tail portion of the bolt.

An adjustable gas system for a firearm includes a gas block, a gas regulator and a plunger. The gas block is configured to be fixed to a barrel of the firearm, and includes a hole configured to receive a gas tube of the firearm. The gas regulator is configured to rotate around the barrel, and includes a plurality of gas port holes of different sizes. The plunger is configured to hold the gas regulator at one of a plurality of angles with respect to the gas block such that a select one of the plurality of gas port holes is aligned with the hole on the gas block to allow a respective amount of gas to flow from the barrel to the gas tube through the select one of the plurality of gas port holes.

An adjustable gas system for a firearm includes a gas block, a gas regulator and a plunger. The gas block is configured to be fixed to a barrel of the firearm, and includes a hole configured to receive a gas tube of the firearm. The gas regulator is configured to rotate around the barrel, and includes a plurality of gas port holes of different sizes. The plunger is configured to hold the gas regulator at one of a plurality of angles with respect to the gas block such that a select one of the plurality of gas port holes is aligned with the hole on the gas block to allow a respective amount of gas to flow from the barrel to the gas tube through the select one of the plurality of gas port holes.

A conversion unit for converting an AR-15 style military assault rifle to a submachine gun includes a central assembly having a magazine well and rear barrel mount. The magazine well can be inserted downwardly into the lower receiver of the assault rifle and accommodates magazines for shorter cartridges. The conversion unit also includes a forearm and barrel assembly and an upper receiver with a stabilizing rail. A pressure equalizing gas operating system eliminates the need for a buttstock with recoil spring. An operating rod extends forward from the upper receiver and into the forearm enclosure. The operating rod is attached to the bolt of the submachine gun and engaged with a reciprocating gas cylinder that surrounds the barrel.

An adjustable gas system for a firearm includes a gas block, a gas regulator and a plunger. The gas block is configured to be fixed to a barrel of the firearm, and includes a hole configured to receive a gas tube of the firearm. The gas regulator is configured to rotate around the barrel, and includes a plurality of gas port holes of different sizes. The plunger is configured to hold the gas regulator at one of a plurality of angles with respect to the gas block such that a select one of the plurality of gas port holes is aligned with the hole on the gas block to allow a respective amount of gas to flow from the barrel to the gas tube through the select one of the plurality of gas port holes.

An adjustable gas system for a firearm includes a gas block, a gas regulator and a plunger. The gas block is configured to be fixed to a barrel of the firearm, and includes a hole configured to receive a gas tube of the firearm. The gas regulator is configured to rotate around the barrel, and includes a plurality of gas port holes of different sizes. The plunger is configured to hold the gas regulator at one of a plurality of angles with respect to the gas block such that a select one of the plurality of gas port holes is aligned with the hole on the gas block to allow a respective amount of gas to flow from the barrel to the gas tube through the select one of the plurality of gas port holes.

A piston for a gas-operated firearm has an elongated body having a head portion adapted to be closely received in the cylindrical bore for reciprocation within the bore, the head portion having a first side toward a forward direction and a second side toward the rearward direction, the body having an operational facility on the second side adapted to transmit an operating force to the action in response to gas pressure on the first side, and the head portion defining a bypass passage between the first side and the second side. The bypass passage may have an adjustment facility adapted to provide selectable resistance to gas flow through the bypass passage. The adjustment facility may be a movable occlusion element that selectably occludes the bypass passage. The occlusion element may be a threaded element. The occlusion element may be a collar that receives a portion of the body.